U.S. Pat. No. 5,936,520, an Analog Sensor Status Detection Single Wire Bus Multiplex System (Luitje, et al) discloses a circuit that monitors both digital and analog sensor readings by polling them from a single wire bus multiplex system. The circuit operates to sequentially address a plurality of smart sensor interfaces, each having an associated sensor, connected to the single wire bus. A voltage signal is supplied on the line that produces a current corresponding to the presence of a sensor at the polled interface and a current corresponding to a sensed digital or analog value where the sensor is of the digital or analog type, respectively. The currents on the bus are copied in a current mirror whose current output is applied to a resistor to produce a voltage, which in turn is converted into a digital number to be analyzed to determine the presence of a sensor at the addressed interface and its status. The current in the circuit is also measured to produce a voltage corresponding to circuit component variations and one corresponding to the contributions of the currents from the power supplies of the interfaces. These voltages correct the calculation of the voltage corresponding to the sensor analog value.
U.S. Pat. No. 5,636,342, Systems and Method for Assigning Unique Addresses to Agents on a System Management Bus, (Jeffries), discloses a system and method for automatically assigning addresses to agents on a system management bus in a computer system without requiring user intervention, i.e., without requiring the user to manually or programmatically set physical or logical switches. The computer system includes a system management bus which preferably uses the I.sup.2 C serial protocol. The bus includes at least one SMB master and a plurality of slaves for performing desired monitoring and control functions in the computer system. According to the present invention, the SMB master assigns unique addresses to each of the SMB slaves automatically and without user intervention. This provides a simpler, more efficient, and less error prone method for assigning addresses to SMB agents. In addition, the system of the present invention automatically assigns unique addresses to new devices inserted on the bus while the bus is operating and thus allows for hot pluggable devices.
U.S. Pat. No. 6,532,506, Communicating With Devices Over a Bus and Negotiating the Transfer Rate Over the Same, (Dunstan, et al.), discloses a system having a first device and a second device coupled to a single wire bus. The second device is operable to receive power from the single wire bus that is due to the first device driving the bus. The second device also communicates with the first device using the single wire bus.
U.S. Pat. No. 6,298,066, Single Wire Bus Interface for Multidrop Applications, (Wettroth, et al.), enables data communications between multiple devices over a single wire bus. This single-wire interface can be used for sensors, amplifiers, analog-to-digital converters (ADCs), or any other circuit which would normally have an electrical output. Advantages of the present invention include a reduction in device pin count, conservation of the limited number of I/O pins on the control device, and reduced board layout complexity. Speaking generally, each slave device coupled to the single wire bus interface is assigned a different response time window. This enables multiple slave devices to respond to an initial trigger signal generated by the master device without overlapping responses being generated on the single wire bus interface. A suitable slave electrical device includes application circuitry providing state information for the electrical device, an input/output pin suitable for making an electrical coupling external to the electrical device, and a single wire bus interface coupled to the input/output pin and the application circuitry. The single wire bus interface has conversion function circuitry defining a specific response time window for the electronic device. Further, the single wire bus interface is responsive to a start signal received on the input/output pin to generate a response signal within the specific response time window, the response signal indicative of the state information for the electrical device.
U.S. Pat. No. 5,809,518, Command/Data Transfer Protocol for One-Wire-Bus Architecture, (Lee), discloses a command protocol for a single wire bus for transmitting and receiving commands and data. The command protocol includes a serial command word which facilitates communication between a host circuit and a slave circuit. The serial command word is divided into portions which can be used to reset the slave circuit, request the slave circuit to identify itself, and to specify the type of data transfer that is to occur between the host circuit and the slave circuit.
U.S. Pat. No. 6,108,751, Single Wire Data Communication Method, (Lee, et al) discloses a system architecture which provides efficient data communication, over a one-wire bus, with a portable data module which does not necessarily include any accurate time base whatsoever. The time base in the module can be extremely crude (e.g. more than 4:1 uncertainty). An open-collector architecture is used, with electrical relations defined to absolutely minimize the drain on the portable module's battery. The protocol has been specified so that the module never sources current to the data line, but only sinks current. The protocol includes signals for read; write-zero; write-one; and reset. Each one-bit transaction is initiated by a falling edge from the host. The time base in the module defines a delay, after which (in write mode) the module tests the data state of the data line. In read mode, after a falling edge the module does or does not turn on its pull-down transistor, depending on the data value. Thus, the host system, after the falling edge, attempts to pull the data line high again, and then tests the potential of the data line to ascertain the data value.
U.S. Pat. No. 6,112,275, Method of Communicating Over a Single Wire Bus Between a Host Device and a Module Device Which Measures Thermal Accumulation Over Time, (Curry, et al.), discloses a method of communicating information between a host device and a potentially portable module device which measures thermal accumulation over time via a temperature controlled counter. The temperature controlled counter may operate using substantially Arrhenius' law. The host device communicates with the portable module via a single wire bidirectional data bus. The single wire bus and one-wire communication protocol allows data flow between a host and a plurality of devices connected to the single wire bus. The single wire bus allows for a great versatility of uses for the portable module.
U.S. Pat. No. 5,210,846, One-Wire Bus Architecture, (Lee), discloses a system architecture which provides efficient data communication, over a one-wire bus, with a portable data module which does not necessarily include any accurate time delay circuit whatsoever. The time delay circuit in the module can be extremely crude. An open-collector architecture is used, with electrical relations defined to absolutely minimize the drain on the portable module's battery. A protocol has been specified so that the module never sources current to a data line of the one-wire bus, but only sinks current. The protocol includes signals for read; write-zero; write-one; and reset. Each one-bit transaction is initiated by a falling edge of a voltage signal from the host. The time delay circuit in the module defines a delay, after which (in write mode) the module tests the data state of the data line. In read mode, after a falling edge of a voltage signal from the host the module does or does not turn on a pull-down transistor, depending on the value of the bit read. Thus, the host system, after the falling edge, attempts to pull the data line high again, and then tests the potential of the data line to ascertain the value of the bit read.
U.S. Pat. No. 5,761,697, Identifiable Modules on a Serial Bus System and Corresponding Identification Methods (Curry, et al.), discloses a single wire data bus that is utilized by a bus master to communicate with and identify electronic devices also connected to the single wire data bus. Each of the electronic devices include a unique ID (identification), wherein the bus master, using a one-wire protocol, can identify all of the electronic devices connected to the single wire data bus.
U.S. Pat. No. 6,239,732, One-Wire Device With a-to-D Converter (Cusey), discloses a low power integrated circuit having analog to digital conversion circuitry capable of receiving a plurality of analog signals and converting them to a digital value. The digital value is then transmitted, upon request, over a single wire bus. The accuracy of the analog to digital conversion circuitry can be calibrated via trim codes stored in an onboard EPROM.